Method for exposing a peripheral area of a wafer and apparatus for performing the same

ABSTRACT

A method and an apparatus for precisely exposing a predetermined width of a peripheral area of a wafer coated with a layer of photoresist material with light from a light source, wherein the wafer is moved when the light is radiated onto the wafer to expose the photoresist layer at the peripheral area of the wafer, an inspection section inspecting whether the light is radiated onto a precise position of the peripheral area of the wafer, whereby by adjusting the position of the light source if the light is not radiated at the precise position of the peripheral area of the wafer requiring exposure while inspecting the light radiated onto the peripheral area of the wafer, the predetermined width of the peripheral area of the wafer is precisely exposed.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a method for exposing aperipheral area of a wafer and an apparatus for performing the same.More particularly, the present invention relates to a method forprecisely exposing a wafer by a predetermined width from a peripheralarea to a predetermined inner portion of the wafer coated withphotoresist and an apparatus for performing the method.

[0003] 2. Description of the Related Art

[0004] As electronic information media devices, such as computers,become more widely used, semiconductor technology also becomes widelyused. From a functional aspect, a semiconductor device is required tooperate at a high speed with a large storing capacitance. Accordingly,semiconductor technology has made great strides recently to develop andimprove the degree of integration as well as increase reliability andresponse speed of semiconductor devices. Accordingly, in the field ofsemiconductor technology, techniques for improving the degree ofintegration in semiconductor devices, such as photolithographictechniques, which are used as fine processing techniques inmanufacturing semiconductor wafers are critical in meeting the currentstrict requirements and demands in semiconductor manufacture.

[0005] As is well known in the field of photolithography technique, aphotoresist film is formed on the wafer on which films for formingpatterns are deposited. Then, a predetermined portion of the photoresistpattern is removed by exposure and developing processes so that thephotoresist pattern is formed on the wafer.

[0006] The photoresist film is made of a photosensitive polymermaterial. The photosensitive polymer material is subject to a chemicalreaction by the light, so the solubility of the photoresist polymermaterial is changed. That is, when the wafer formed with the photoresistfilm is exposed to the light through a photo mask provided with finecircuits, the chemical reaction selectively occurs in a predeterminedportion of the photoresist film, on which the light is radiated, so thatthe predetermined portion of the photoresist film is changed tonon-soluble material or the solubility thereof is increased as comparedwith solubility of the other part of the photoresist film. By developingthe photoresist film using a film developer, the photoresist pattern isformed. The photoresist pattern may be used as a mask when an etchingprocess or an ion implanting process is carried out.

[0007] The photo mask is fabricated such that the photoresist patternmay be formed on a chip area of the wafer. Therefore, a peripheral areaof the wafer, in which the chip is not formed, has no photoresistpatterns. If the photoresist pattern is formed by using a positivephotoresist, which is changed to the soluble material when the light isradiated thereon, the photoresist still remains in the peripheral areaof the wafer after the wafer has been developed, since the peripheralarea of the wafer is not exposed to the light. The photoresist remainingin the peripheral area of the wafer frequently makes contact with awafer chuck or a teaser, so the wafer may be contaminated by thephotoresist. For this reason, a side rinse process is carried out byspraying a cleaning liquid, such as acetone, on the peripheral area ofthe wafer to remove the photoresist from the peripheral area of thewafer when the photoresist is coated on the wafer. However, the siderinse process is not capable of completely removing the photoresistremaining in the peripheral area of the wafer.

[0008] In an effort to solve at least the above problem, the peripheralarea of the wafer is separately exposed and developed after thephotoresist pattern is formed on the wafer coated with the photoresist,thereby removing the photoresist from the peripheral area of the wafer.

[0009]FIG. 1 illustrates a conventional exposure device for exposing aperipheral area of a wafer.

[0010] Referring to FIG. 1, the exposure device for exposing aperipheral area of a wafer has a wafer chuck 12 on which the wafer Wformed with a photoresist pattern 10 is loaded. The wafer chuck 12 has asize smaller than a size of the wafer W. A driving section 14 isoperatively associated with the wafer chuck 12 to horizontally androtatably drive the wafer chuck 12. A light source 16 is fixedlyinstalled above the wafer W to radiate the light toward the peripheralarea of the wafer W.

[0011] In order to expose the entire peripheral area of the wafer Wusing the conventional exposure device, the wafer is moved by drivingsection 14 while the light is radiated onto the peripheral area of thewafer W from the light source 16 until the entire peripheral area of thewafer W is exposed to the light.

[0012] More particularly, the wafer W formed with the photoresistpattern 10 is loaded on the wafer chuck 12. Then, the light is radiatedon a predetermined portion of the peripheral area and an outer areabeyond an edge portion of the wafer W. The light is radiated onto thewafer W such that the photoresist film 10 formed on the peripheral areaof the wafer W may be exposed to the light.

[0013] While the light is being radiated onto the wafer W, the waferchuck 12 is driven to move the wafer W in such a manner that apredetermined portion of the photoresist film 10 formed on theperipheral area of the wafer W is exposed to the light. The wafer chuck12 is horizontally driven parallel to a flat zone of the wafer W whenthe light is radiated onto the flat zone of the wafer W, and isrotatably driven when the light is radiated onto the peripheral area ofthe wafer W.

[0014] However, the above method cannot precisely expose thepredetermined portion of the peripheral area of the wafer W. That is, inorder to precisely expose the predetermined portion of the peripheralarea of the wafer W while rotating the wafer W, a center of the wafer Wmust precisely match a center of the wafer chuck 12. In addition, thewafer chuck 12 must be horizontally maintained while the rotationaloperation is being carried out. However, the tolerance may be exceededwhen the wafer W is loaded on the wafer chuck 12 by a robot arm or whenthe wafer chuck 12 is rotated, so precise exposure is difficult.

[0015]FIG. 2A illustrates a top plan view of a wafer that has beencorrectly exposed to the light. FIG. 2B illustrates a top plan view of awafer that has been incorrectly exposed to the light.

[0016] The wafer W shown in FIG. 2A has exposed portions 20 a and 20 bhaving uniform widths in the peripheral area of the wafer W. However,the wafer W as shown in FIG. 2B has not been uniformly exposed to thelight so that widths of exposed portions 20 c and 20 d of the peripheralarea of the wafer W are unevenly formed.

[0017] The large width of exposed portion 20 d of the wafer shown inFIG. 2B may cause failure of a main chip since a portion of thephotoresist pattern formed on the main chip is exposed to the light. Inaddition, particles may be generated by the photoresist remaining in anarea of the exposed portion 20 c, thereby also resulting in failure ofthe chip.

SUMMARY OF THE INVENTION

[0018] The present invention has been made to solve at least some of theproblems of the prior art. Accordingly, it is a feature of an embodimentof the present invention to provide a method for precisely exposing apredetermined portion of a peripheral area of a wafer coated withphotoresist.

[0019] Another feature of an embodiment of the present invention is toprovide an apparatus for performing the method.

[0020] To provide the first feature of the present invention, there isprovided a method for exposing a peripheral area of a wafer as follows:a photoresist film formed on a peripheral area of a wafer is exposed byradiating a light toward the peripheral area of the wafer while movingthe wafer; whether the light is uniformly radiated onto thepredetermined width of the peripheral area of the wafer is inspectedwhen the exposing is carried out; and a position of the light to beradiated onto the peripheral area of the wafer is adjusted if the lightdeviates from the predetermined width of the peripheral area of thewafer.

[0021] To provide the second feature of the present invention, there isprovided an apparatus for exposing a peripheral area of a wafer. Theapparatus includes a wafer chuck on which a wafer formed with aphotoresist film is loaded; a first driving section operativelyassociated with the wafer chuck to drive the wafer chuck; a light sourceinstalled above the peripheral area of the wafer to generate light; aninspecting section for inspecting whether the light is preciselyradiated from the light source onto the peripheral area of the wafer;and a second driving section operatively associated with both theinspecting section and the light source to drive the light source insuch a manner that the light is precisely radiated on the peripheralarea of the wafer.

[0022] According to the present invention, the photoresist film formedon the peripheral area of the wafer is exposed by radiating the lightonto the peripheral area of the wafer while moving the wafer. Inaddition, the position of the light source is adjusted while inspectingthe light radiated onto the peripheral area of the wafer, so that thepredetermined width of the peripheral area of the wafer may be preciselyexposed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above features and advantages of the present invention willbecome more apparent by describing in detail preferred embodimentsthereof with reference to the attached drawings in which:

[0024]FIG. 1 illustrates a conventional apparatus for exposing aperipheral area of a wafer;

[0025]FIGS. 2A and 2B illustrate top plan views of wafers, which arecorrectly and incorrectly exposed to light, respectively;

[0026]FIG. 3 is a schematic diagram illustrating an apparatus forexposing a peripheral area of a wafer according to a first embodiment ofthe present invention;

[0027]FIG. 4 is a block diagram illustrating the construction of aninspecting section and a second driving section of the apparatus shownin FIG. 3;

[0028]FIG. 5 is a flow chart illustrating method steps for exposing theperipheral area of a wafer according to the first embodiment of thepresent invention;

[0029]FIG. 6 illustrates a top plan view of a wafer illustrating amethod for exposing the peripheral area of the wafer using the apparatusshown in FIG. 3;

[0030]FIG. 7 is a schematic diagram illustrating an apparatus forexposing a peripheral area of a wafer according to a second embodimentof the present invention;

[0031]FIG. 8 is a block diagram illustrating the construction of aninspecting section and a second driving section of the apparatus shownin FIG. 7;

[0032]FIG. 9 is a flow chart illustrating method steps for exposing theperipheral area of a wafer according to the second embodiment of thepresent invention; and

[0033]FIG. 10 illustrates a top plan view of a wafer illustrating amethod for exposing the peripheral area of the wafer using the apparatusshown in FIG. 7.

DETAILED DESCRIPTION OF THE INVENTION

[0034] Korean Patent Application No. 2001-11540, filed Mar. 6, 2001, andentitled: “Method for Exposing a Peripheral Area of a Wafer andApparatus for Performing Same,” is incorporated by reference herein inits entirety.

[0035] Hereinafter, preferred embodiments of the present invention willbe described in detail with reference to the accompanying drawings.

[0036]FIG. 3 is a schematic diagram illustrating an apparatus forexposing a peripheral area of a wafer according to a first embodiment ofthe present invention.

[0037] Referring to FIG. 3, a wafer W is loaded on a wafer chuck 30. Thewafer W loaded on the wafer chuck 30 is formed with a photoresist film32. The photoresist film 32 is exposed through a photo mask having finecircuits so that a photoresist pattern is formed on the upper portion ofthe wafer W. When the photoresist film 32 is formed on the upper portionof the wafer W, a side rinse is carried out by injecting a cleaningliquid including acetone toward the peripheral area of the wafer W, sothat the photoresist formed on the peripheral area of the wafer W isremoved. The wafer chuck 30 has a size smaller than a size of the waferW loaded thereon.

[0038] A first driving section 34 is operatively associated with thewafer chuck 30 to drive the wafer chuck 30. The first driving section 34has a rotating shaft 34 a that supports a lower portion of the waferchuck 30 and rotates the wafer chuck 30. A rail 34 b is coupled to alower portion of the rotating shaft 34 a. The rail 34 b provides a routefor moving the wafer chuck 30 in a direction parallel to a flat zone ofthe wafer W loaded on the wafer chuck 30. A moving section 34 c isoperatively associated with the rotating shaft 34 a to drive therotating shaft 34 a in a direction parallel to the flat zone of thewafer W by way of the rail 34 b.

[0039] A light source 36 is installed above the peripheral area of thewafer W loaded on the wafer chuck 30. The light source 36 is positionedsuch that light generated by the light source 36 is radiated over theperipheral area of the wafer W and an outer area beyond an edge portionof the wafer W.

[0040] An inspecting section 38 is provided to inspect whether the lightgenerated by the light source 36 is precisely radiated along apredetermined width of the peripheral area of the wafer W. In addition,a second driving section 40 is operatively associated with both theinspecting section 38 and the light source 36 to drive the light source36.

[0041]FIG. 4 is a block diagram illustrating the construction of theinspecting section 38 and the second driving section 40 of the apparatusshown in FIG. 3.

[0042] Referring to FIG. 4, the inspecting section 38 includes a firstdetecting part 38 a installed remote from a rear surface of theperipheral area of the wafer W for detecting the light radiated towardthe outer area beyond the peripheral edge portion of the wafer W andoutputting an optical datum of the detected light. The first detectingpart 38 a includes a sensing part 38 a 1 for sensing an intensity ofradiation of the light radiated toward the outer area beyond theperipheral edge portion of the wafer W. The optical datum of thedetected light is based on the intensity of the radiation of the lightas sensed by the sensing part 38 a 1 and as outputted by the outputtingpart 38 a 2. A first determining part 38 b is provided to receive theoptical datum from the first detecting part 38 a. The first determiningpart 38 b compares the optical datum with a reference optical datum todetermine whether the optical datum is within a predetermined, allowablerange of values. The reference optical datum is predetermined as anoptical datum that is detected by the first detecting part 38 a when thepredetermined width of the peripheral area of the wafer W is uniformlyexposed to the light. In addition, a first calculating part 38 c isoperatively associated with the first determining part 38 b. The firstcalculating part 38 c receives an error value of the optical datum fromthe determining part 38 b to calculate a position of the light to beradiated and a position datum of the light source for preciselyradiating the light to the position.

[0043] When a predetermined width of the peripheral area of the wafer isuniformly exposed, the intensity of radiation of the light radiatedtowards the outer area beyond the edge portion of the wafer W isconstantly maintained. Therefore, the position datum of the light source36, which is a distance to be moved to an inner or outer direction ofthe wafer W from the position of the light source 36, may be calculatedbased on the error value between the intensity of radiation of thedetected light with a reference intensity of radiation of the light andthe error value thereof.

[0044] The second driving section 40, which is operatively associatedwith both inspecting section 38 and the light source 36 to drive thelight source 36, is coupled to a motor 40 b to horizontally move thelight source 36 in an inner or an outer direction of the wafer W loadedon the wafer chuck 30. In addition, a control section 40 a is providedto control the operation of the motor 40 b based on the position datuminputted from the inspecting section 38.

[0045] Accordingly, the apparatus is able to precisely expose apredetermined width of the peripheral area of the wafer W by moving thelight source 36 using the second driving section 40.

[0046] Hereinafter, a method for exposing the peripheral area of thewafer W by using the apparatus shown in FIG. 3 will be described.

[0047]FIG. 5 is a flow chart illustrating method steps for exposing theperipheral area of a wafer according to a first embodiment of thepresent invention.

[0048] Referring to FIGS. 3, 4 and 5, a photoresist film 32 is formed onwafer W. In step S10, the wafer W is loaded on the wafer chuck 30, whichis horizontally and rotatably driven. In step S12, the light is radiatedonto a predetermined portion of the peripheral area of the wafer Wloaded on the wafer chuck 30. The light is radiated from the lightsource 36 over the peripheral area and the outer area beyond an edgeportion of the wafer W. In addition, the light source 36 is positionedsuch that the predetermined width of the peripheral area of the wafer Wis exposed to the light when a center of the wafer W matches a center ofthe wafer chuck 30.

[0049] In step S14, the photoresist film 32 formed on the peripheralarea of the wafer W is exposed by radiating the light from the lightsource 36 while moving the wafer W by driving the wafer chuck 30. Thatis, when the light is radiated onto a flat zone of the wafer W, thewafer chuck 30 moves in a direction parallel to the flat zone of thewafer W. Accordingly, the light is radiated onto the wafer W along theflat zone of the wafer W by a predetermined width so that thephotoresist film 32 formed on the flat zone of the wafer W is exposed.In addition, when the light is radiated onto the peripheral area of thewafer W except for the flat zone of the wafer W, the wafer chuck 30 isrotated. Accordingly, the light is radiated along a predetermined widthof the peripheral area of the wafer W so that the photoresist film 32formed on the peripheral area of the wafer W is exposed.

[0050] In step S16, when the peripheral area of the wafer W is exposedwhile driving the wafer chuck 30, the inspecting section 38 detects thelight radiated toward the outer area beyond the edge portion of thewafer W and inspects whether the light is radiated onto thepredetermined width of the peripheral area of the wafer W. Moreparticularly, the first detecting part 38 a detects the light radiatedtoward the outer area beyond the edge portion of the wafer W and outputsthe optical datum thereof. The optical datum is an intensity ofradiation of the detected light. In addition, the first determining part38 b receives the optical datum from the first detecting part 38 a. Whenthe predetermined width of the peripheral area of the wafer W isuniformly exposed, the first determining part 38 b compares the opticaldatum detected by the first detecting part 38 a with a reference opticaldatum to determined whether the optical datum is within a predetermined,allowable range of values. The first calculating part 38 c thencalculates the precise position datum of the light to be radiated basedon the error value inputted from the first determining part 38 b.

[0051] If the outputted optical datum is larger than the referenceoptical datum, the width of the peripheral area of the wafer W, to whichthe light is radiated, is narrowed. If the outputted optical datum issmaller than the reference optical datum, the width of the peripheralarea of the wafer W is extended or widened. Accordingly, in order toradiate the light onto a predetermined width of the peripheral area ofthe wafer precisely, the distance datum for horizontal movement of thelight source 36 in the inner or outer direction of the wafer W iscalculated based on the error value obtained by the first determiningpart 38 b.

[0052] In step S18, if the light radiated onto the peripheral area ofthe wafer W does not match the predetermined width, the position of thelight is adjusted by moving the position of the light source 36. Thatis, the control section 40 a of second driving section 40 receives thecalculated position datum and drives the motor 40 b based on theposition datum to horizontally move the light source 36 in the inner orouter direction of the wafer W.

[0053]FIG. 6 illustrates a top plan view of a wafer illustrating methodsteps for exposing the peripheral area of the wafer by using theapparatus shown in FIG. 3.

[0054] Referring to FIG. 6, the wafer chuck 30 is driven to expose theperipheral area of the wafer W loaded thereon while the light isradiated from the light source 36 onto the peripheral area of the waferW. At this time, the optical datum of the light 36 a radiated toward theouter area beyond the edge portion of the wafer W is detected and thelight source 36 is horizontally moved in the inner or outer direction ofthe wafer W based on the optical datum.

[0055] Accordingly, the predetermined width of the peripheral area ofthe wafer W may be precisely exposed by moving the position of the lightsource 36 even when the wafer W is not accurately positioned on thewafer chuck 30 or a tolerance is exceeded when the wafer chuck 30 isrotated.

[0056]FIG. 7 is a schematic diagram illustrating an apparatus forexposing a peripheral area of a wafer according to a second embodimentof the present invention.

[0057] The method and apparatus of the second embodiment is similar tothe method and apparatus of the first embodiment shown in FIGS. 3 to 5,except for an addition of an inspecting section for inspecting whetherthe light is precisely radiated onto the peripheral area of the wafer.Hereinafter, an apparatus according to the second embodiment of thepresent invention will be described with reference to FIG. 7.

[0058] The apparatus according to the second embodiment of the presentinvention has a wafer chuck 50 on which the wafer W coated with aphotoresist film 52 is loaded, including a first driving section 54, arotating shaft 54 a installed at a center of a lower portion of thewafer chuck 50 to rotate the wafer chuck 50, a rail 54 b which iscoupled to the lower portion of the rotating shaft 54 a to provide aroute for horizontally driving the wafer chuck 50 and a moving section54 c for moving the wafer chuck 50 by way of the rail 54 b. A lightsource 56 is installed above the peripheral area of the wafer W togenerate light. The structure and function of a second driving section60, which drives the light source 56 such that a predetermined width ofthe peripheral area of the wafer W is exposed, are identical to those ofthe second driving section 40 according to the first embodiment of thepresent invention.

[0059] In the second embodiment of the present invention, the inspectingsection 58 for inspecting whether the light generated from the lightsource is precisely radiated onto the peripheral area of the wafer W hasa structure that is different from the structure of the inspectingsection according to the first embodiment of the present invention. FIG.8 is a block diagram illustrating the construction of the inspectingsection 58 and the second driving section 60 of the apparatus shown inFIG. 7.

[0060] Referring to FIGS. 7 and 8, the inspecting section 58 includes asecond detecting part 58 a horizontally remote from an edge portion ofthe wafer W loaded on the wafer chuck 50 to detect a distance betweenthe edge portion of the wafer W and a reference point that ishorizontally positioned with respect to the edge portion of the wafer W.A second determining part 58 b is provided to receive the distance datumfrom the second detecting part 58 a and to compare the detected distancedatum with a reference distance datum to determine whether the detecteddistance datum is within a predetermined, allowable range of values. Thereference distance datum is a distance between the edge portion of thewafer W and the reference point, which is detected when thepredetermined width of the peripheral area of the wafer is uniformlyexposed to the light. A second calculating part 58 c is operativelyassociated with the second determining part 58 b to precisely calculatethe position of the light to be radiated and the position datum of thelight source 56 for precisely radiating the light to the position basedon an error value of the distance datum obtained by the seconddetermining part 58 b.

[0061] When the predetermined width of the peripheral area of the waferW is uniformly exposed, the distance between the edge portion of thewafer W and the reference point is constantly maintained. Therefore, theposition datum of the light source 56, which is a distance for movingthe light source 56 in an inner or an outer direction of the wafer W toprecisely radiate the light to the peripheral area of the wafer W, maybe calculated based on the error value of the distance datum.

[0062] The second driving section 60 is coupled to a motor 60 b tohorizontally move the light source 56 in an inner or an outer directionof the wafer W loaded on the wafer chuck 50. In addition, a controlsection 60 a is provided to control the operation of the motor 60 bbased on the position datum inputted from the inspecting section.

[0063] Accordingly, the apparatus according to the second embodiment ofthe present invention is able to precisely expose the predeterminedwidth of the peripheral area of the wafer W by moving the light sourceusing the second driving section 60.

[0064] Hereinafter, a method for exposing the peripheral area of thewafer W using the apparatus according to the second embodiment of thepresent invention will be described.

[0065]FIG. 9 is a flow chart illustrating method steps for exposing theperipheral area of a wafer according to the second embodiment of thepresent invention.

[0066] Referring to FIGS. 7, 8 and 9, the wafer W coated with aphotoresist film 52 is loaded on the wafer chuck 50, in step S30.

[0067] Then, in step S32, the light is radiated onto a predeterminedportion of the peripheral area of the wafer W. The light source 56 ispositioned such that only a predetermined width of the peripheral areaof the wafer W is exposed to the light when a center of the wafer Wmatches a center of the wafer chuck 50.

[0068] Then, in step S34, the distance between the edge portion of thewafer W loaded on the wafer chuck and the reference point is detected.The detected distance datum is compared with the predetermined referencedistance datum to calculate the position datum of the light source 56and thereby reset, if necessary, the position of the light source 56.

[0069] In step S36, the photoresist film 52 formed on the peripheralarea of the wafer W is exposed by radiating the light onto theperipheral area of the wafer W while moving the wafer W by driving thewafer chuck 50. The light is radiated over the peripheral area and anouter area beyond an edge portion of the wafer W.

[0070] In step S38, when the peripheral area of the wafer W is exposedwhile driving the wafer chuck 50, the distance between the edge portionof the wafer W and the reference point is detected to inspect whetherthe light is radiated onto the predetermined width of the peripheralarea of the wafer W. More particularly, the second detecting part 58 adetects the distance between the edge portion of the wafer W and areference point that is horizontally spaced from the edge portion of thewafer W. The reference point is positioned on an extension line that isextended from a center of the wafer beyond the edge portion of the waferW. In addition, the second determining part 58 b receives the distancedatum from the second detecting part 58 a. The second determining part58 b compares the distance datum with the reference distance datum todetermine whether the distance datum lies within a predetermined,allowable range of values. The reference distance datum is determined asa distance between the edge portion of the wafer and the reference pointthat is detected when the predetermined width of the peripheral area ofthe wafer is uniformly exposed to the light. The second calculating part58 c calculates the precise position datum of the light to be radiatedbased on the error value inputted from the second determining part 58 b.If the detected distance datum is larger than the reference distancedatum, the width of the peripheral area of the wafer W, onto which thelight is radiated, is narrowed. If the detected distance datum issmaller than the reference distance datum, the width of the peripheralarea of the wafer W is extended or widened. Accordingly, in order toradiate the light onto the predetermined width of the peripheral area ofthe wafer precisely, the distance datum for horizontal movement of thelight source 56 in the inner or outer direction of the wafer W iscalculated based on the error value obtained by the first determiningpart 58 b.

[0071] In step S40, if the light radiated onto the peripheral area ofthe wafer W does not match the predetermined width, the position of thelight is adjusted by moving the light source 56. That is, the controlsection 60 a of second driving section 60 receives the calculatedposition datum and drives the motor 60 b operatively associated with thelight source based on the position datum to horizontally move the lightsource 56 in the inner or outer direction of the wafer W.

[0072]FIG. 10 illustrates a top plan view of a wafer illustrating methodsteps for exposing the peripheral area of the wafer using the apparatusshown in FIG. 7.

[0073] Referring to FIG. 10, the wafer chuck 50 is driven to expose theperipheral area of the wafer W loaded thereon while radiating the lightfrom the light source 56 onto the peripheral area of the wafer W. Atthis time, the distance between the edge portion of the wafer and thepredetermined reference point is detected by the inspecting station 58and the light source 56 is horizontally moved in the inner or outerdirection of the wafer W based on the detected distance datum.Accordingly, the predetermined width of the peripheral area of the waferW may be precisely exposed by moving the light source 56 even when thewafer W is not accurately positioned on the wafer chuck 50 or atolerance is exceeded when the wafer chuck 50 is rotated.

[0074] As described above, according to the present invention, theposition of the light may be adjusted by inspecting whether the light isprecisely radiated onto the peripheral area of the wafer, in order thatthe predetermined width of the peripheral area of the wafer may beprecisely exposed. Accordingly, faulty exposure of the wafer, whichoccurs when the predetermined width of the wafer to be exposed to thelight is irregularly formed, may be prevented, thereby increasing theproduction yield of the semiconductor device.

[0075] While the present invention has been described in detail withreference to preferred embodiments thereof, it should be understood bythose of ordinary skill in the art that various changes, substitutionsand modifications may be made hereto without departing from the scope ofthe invention as defined in the following claims.

1. A method for exposing a peripheral area of a wafer, comprising: (i)exposing a photoresist film formed on a peripheral area of a wafer byradiating a light toward the peripheral area of the wafer while movingthe wafer; (ii) inspecting whether the light is uniformly radiated ontoa predetermined width of the peripheral area of the wafer when theexposing is carried out; and (iii) adjusting a position of the light tobe radiated onto the peripheral area of the wafer if the light deviatesfrom the predetermined width of the peripheral area of the wafer.
 2. Themethod as claimed in claim 1, wherein, in (i), the wafer is moved in adirection parallel to a flat zone of the wafer when the light isradiated onto the flat zone of the wafer and the wafer is horizontallyrotated when the light is radiated onto the peripheral area of thewafer.
 3. The method as claimed in claim 1, wherein, in (i), the lightis radiated over the peripheral area and an outer area beyond an edgeportion of the wafer.
 4. The method as claimed in claim 1, wherein (ii)comprises: a) detecting the light radiated to an outer area beyond anedge portion of the wafer and outputting an optical datum thereof; b)comparing the outputted optical datum with a reference optical datum todetermine whether the outputted optical datum is within a predetermined,allowable range of values; and c) calculating a position datum for thelight to be radiated based on an error value between the referenceoptical datum and the outputted optical datum.
 5. The method as claimedin claim 4, wherein the optical datum is an intensity of radiation ofthe light detected by a light detecting section.
 6. The method asclaimed in claim 4, wherein the reference optical datum is an opticaldatum that is detected when the predetermined width of the peripheralarea of the wafer is uniformly exposed to light.
 7. The method asclaimed in claim 1, wherein (ii) comprises: a) detecting a distancebetween an edge portion of the wafer, which includes a portion exposedto the light, and a reference point, which is positioned on an extensionline extended from a center of the wafer beyond the edge portion of thewafer; b) comparing a detected distance datum with a reference distancedatum to determine whether the detected distance is within apredetermined, allowable range of values; and c) calculating a preciseposition datum for the light to be radiated based on an error valuebetween the reference distance datum and the detected distance datum. 8.The method as claimed in claim 7, wherein the reference distance datumis determined as a distance between the edge portion of the wafer andthe reference point, which is detected when the predetermined width ofthe peripheral area of the wafer is uniformly exposed to the light. 9.The method as claimed in claim 1, wherein, prior to (i), an error valuebetween a distance datum from an edge portion of the wafer to a lightdetecting section and a reference distance datum is obtained, and aposition datum for the light to be radiated is calculated to compensatefor the position of the light.
 10. The method as claimed in claim 1,wherein, in (iii), the position of the light is moved to an innerportion or an outer portion of the wafer based on a position datum ofthe light inspected in (ii). 11-19. (Cancelled)